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Bureau of Mines Information Circular/1982 






m 




Predicted Characteristics of Waste 
Materials prom the Processing 
of Manganese Nodules 

By Benjamin W. Haynes and Stephen L. Law 




UNITED STATES DEPARTMENT OF THE INTERIOR 



,f ,•■ 



Information Circular 8904 



•1 



Predicted Characteristics of Waste 
Materials From the Processing 
of Manganese Nodules 

By Benjamin W. Haynes and Stephen L. Law 




UNITED STATES DEPARTMENT OF THE INTERIOR 
James G. Watt, Secretary 

BUREAU OF MINES 
Robert C. Horton, Director 



As the Nation's principal conservation agency, the Department of the Interior 
has responsibility for most of our nationally owned public lands and natural 
resources. This includes fostering the wisest use of our land and water re- 
sources, protecting our fish and wildlife, preserving the environmental and 
cultural values of our national parks and historical places, and providing for 
the enjoyment of life through outdoor recreation. The Department assesses 
our energy and mineral resources and works to assure that their development is 
in the best interests of all our people. The Department also has a major re- 
sponsibility for American Indian reservation communities and for people who 
live in Island Territories under U.S. administration. Tt4^Q 



:m 



This publication has been cataloged as follows: 



Haynes, Benjamin W 

Predicted characteristics of waste materials from the processing 
of manganese nodules. 

(Information circular/ U.S. Dept. of the Interior, Bureau of Mines ; 
8904) 

Bibliography: 10 

Supt. of Docs, no.: I 28.27:8904. 

1. Manganese— Metallurjjy— Waste disposal. 2. Manganese nodules. 
3. Tailings (Metaliurgy)-Analysis. I. Law, Stephen L. II. Title. 
III. Series: Information circular (United States. Bureau of Mines) ; 
8904. 

-TN2&5ry4- [TD899.M43] 622s [622'. 34629] 82-600257 



For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 



CONTENTS 



Page 

Abstract 1 

Introduction 2 

Process descriptions 4 

Gas reduction and ammoniacal leach process ... 4 

Cuprion ammoniacal leach process 4 

High-temperature and high-pressure sulfuric acid 

leach process 5 

Reduction and hydrochloric acid leach process . . 5 

Smelting and sulfuric acid leach process 7 

Physical characteristics 7 

Gas reduction and Cuprion ammoniacal leach 

processes 8 



Page 

High-temperature and high-pressure sulfuric acid 

leach process 8 

Reduction and hydrochloric acid leach process . . 8 

Smelting and sulfuric acid leach process 8 

Chemical characteristics 8 

Gas reduction and Cuprion ammoniacal leach 

processes 8 

High-temperature and high-pressure sulfuric acid 

leach process 9 

Reduction and hydrochloric acid leach process . . 9 

Smelting and sulfuric acid leach process 10 

Summary and conclusions 10 

References 10 



ILLUSTRATIONS 

1. Area of prime interest for first-generation nodule mining, Clarion-Clipperton Fracture Zone area 2 

2. Gas reduction and ammoniacal leach process 4 

3. Cuprion ammoniacal leach process 5 

4. High-temperature and high-pressure sulfuric acid leach process 6 

5. Reduction and hydrochloric acid leach process 6 

6. Smelting and sulfuric acid leach process 7 



TABLES 



Composition of Clarion-Clipperton Fracture Zone area Pacific manganese nodules 3 

Predicted physical characteristics of manganese nodule reject waste material 8 

Physical composition of Cuprion pilot plant-generated reject waste material 8 

Predicted chemical composition of manganese nodule reject waste material from leach processes 9 

Chemical composition of Cuprion pilot plant-generated reject waste material 9 

EP toxicity results on Cuprion pilot plant-generated reject waste material 9 



Iv 



UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 

cm/sec centimeters per ng/g nanograms per pcf pounds per cubic 

second gram foot 

\xg g micrograms per pet percent psi pounds per square 

gram inch 

^m micrometer pg/g picograms per wt-pct weight-percent 

gram "^ 



PREDICTED CHARACTERISTICS OF WASTE MATERIALS FROM THE 
PROCESSING OF MANGANESE NODULES 



By Benjamin W. Haynes^ and Stephen L. Law^ 



ABSTRACT 



As part of the first-order assessment of potential manganese nodule processing reject 
waste materials, the Bureau of Mines estimated the physical and chemical characteristics 
of reject waste materials that would be generated from each of five potential process 
flowsheets. These processes were chosen because of their economic and technical 
feasibility for first-generation nodule processing. A brief description of the five processes is 
given to show process inputs and outputs. The physical characteristics are predicted based 
on land-based laterite processing where applicable, and where no land-based analog 
exists, on the basis of process chemistry. The probable chemical characteristics such as 
element content and compound form are tabulated for each process for 16 elements: As, 
Ba, Be, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Tl, and Zn. These elements were 
chosen based on their presence on the toxic substance list of priority pollutants, EP toxicity 
criteria, and major and minor elements of economic importance (Co, Fe, Mn, and Mo). 

Physical and chemical analyses as well as results of the EP toxicity test of one 
Industrially supplied pilot plant reject waste material are presented. 

' Supervisory research chemist, Avondaie Research Center, Bureau of Mines, Avondale, Md. 
^ Research supervisor, Avondale Research Center, Bureau of Ivtines, Avondale, Md. 



INTRODUCTION 



This report is the initial effort of the Bureau of Mines to 
document the results of a research project entitled "Analysis 
and Characterization of Manganese Nodule Processing 
Rejects." Deep seabed mining for manganese nodules, 
including the processing of nodules to recover value metals, 
raises a variety of environmental, social, and economic 
considerations. To address the waste management aspects 
of the recovery of value metals from nodules, the National 
Oceanic and Atmospheric Administration (NOAA) of the 
Department of Commerce, the Environmental Protection 
Agency (EPA), and the Department of the Interior's Bureau of 
Mines and Fish and Wildlife Service, after consultation with 
affected and concerned interests, have agreed to embark on 
a multiyear cooperative research program which has the 
following overall objective: 

"To provide information needed by Federal and State 
agencies in preparation for receipt of industry's 
commercial waste management plans." 

Under the Deep Seabed Hard Mineral Resources Act of 
1980 (PL 96-283), NOAA has been designated as the lead 
agency in developing terms, conditions, and restrictions for 
the proposed mining of nodules and for the disposal of 
wastes. The NOAA-funded research conducted by the 
Bureau has the objective of obtaining a "first-order chemical 
and physical characterization of rejects from the types of 



manganese nodule processing techniques representative of 
those being developed by industry." The final product of this 
research will be a technical report that can be used by (a) 
industry and environmental scientists in subsequent re- 
search to assess the potential effects of waste management 
alternatives; and (b) regulatory agencies in the determination 
of the standards and test requirements to be met. This is 
expected to facilitate the development of a basic framework 
that accommodates the desire to assure good waste 
management practices and assist in the development of a 
new minerals processing industry. 

To meet the objective of characterization of the reject 
waste material from the several potential first-generation 
process schemes, a knowledge of the nodule feed material 
and the processes considered feasible for first-generation 
processing plants is necessary. A report has been prepared 
describing the mineralogical and elemental characteristics of 
Pacific manganese nodules (7).^ A second report describing 
the five most feasible process flowsheets for first-generation 
plants has also been prepared (6). Based on the information 
in these two reports, this report predicts the physical and 
chemical characteristics of manganese nodule reject waste 
material for each of the five processes. Other types of wastes 

^ italicized numbers in parentheses refer to items in the list of references at 
the end of this report. 



40 



30 



flC 

o 

z 

UJ 

o 



20 



10 



MmM United States !ii;ii:::i 



Hawaiian 

^K. Islands 




cui^' 



B\0^ 



f^^^c 



■vvjv^t 




zot*t 



cO^^ 



^?^^ 



H ^^"^ 



-jov^t 



1.0^^ 



J L 



160 



140 120 

LONGITUDE WEST 



100 



Figure 1. — Area of prime interest for first-generation nodule mining, Clarion-Clipperton Fracture Zone 
area. 



generated in these processes, such as scrubber sludges, 
flyash, and electrowinning sludges, are not included in this 
report. These wastes constitute only a small fraction (<15 
pet) of the total wastes generated for the processes 
considered in this report, have compositions that are 
generally well established, and have been detailed in a 
previous report (2). 

Based on available information, the area of prime interest 
for first-generation nodule mining is that area between the 
Clarion and Clipperton Fracture Zones (CC-zone area) of the 
northeast equatorial Pacific shown in figure 1 . Table 1 gives 
the composition of CC-zone area nodules based on available 
data (7). The predictions of physical and chemical character- 
istics for the five processes will be based on CC-zone area 
nodule composition. 

The types of processes considered most technically 
feasible for first-generation nodule processing are as follows: 

1 . Gas reduction and ammoniacal leach. 

2. Cuprion ammoniacal leach. 

3. High-temperature and high-pressure sulfuric acid 
leach. 

4. Reduction and hydrochloric acid leach. 

5. Smelting and sulfuric acid leach. 

The two ammoniacal and the high-temperature and 
high-pressure sulfuric acid processes are designed to 
recover three metals (Co, Cu, and Ni) and the other two 
processes are designed to recover four metals (Co, Cu, Ni, 
and Mn). 

Each process waste will be discussed in two sections, one 
dealing with physical characteristics and the other dealing 
with chemical characteristics. In the chemical characteristics 
section, the elements discussed are the following 18 
elements of potential economic and/or environmental in- 
terest: Ag, As, Ba, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, 
Pb, Sb, Se, Tl, and Zn. Thirteen of these elements were 
chosen because they are listed as priority pollutants under 
the Toxic Substance Control Act of 1976 (PL 94-469). Cobalt, 



iron, manganese, and molybdenum are included because 
they are major constituents of nodules and/or are of 
economic importance; and barium is included because of its 
presence on the EPA list of leachable metals in the Extraction 
Procedure (EP) toxicity test (4-5). Based on the information 
in the report on the mineralogical and elemental description 
of Pacific nodules (7), the concentration level for each of the 
18 elements in Pacific nodules for the CC-zone area is given 
in table 1 . 

EPA listed levels for eight extractable metals in its EP 
toxicity test (4-5). If the leachate of a material subjected to 
this procedure contains Ag, As, Ba, Cd, Cr, Hg, Pb, and/or Se 
at 100 times the National Drinking Water Standard, that 
waste is considered hazardous under the toxicity definition. 
In order for a material to exceed these limits for mercury and 
silver, it must contain 4 jxg/g and 100 (xg/g of mercury and 
silver respectively; and all must be leachable. Concentrations 
of these two elements are well below those upper limits in all 
manganese nodules. In order for mercury or silver to exceed 
this limit, they must be concentrated during processing by 
factors of 50 and 2,500 respectively. Because only a small, if 
any, concentration factor is involved in the five processes, it 
is extremely unlikely that the levels could be attained. The 
remaining 16 elements will be discussed in each process 
section. 

In considering the processing of nodules, the three major 
mineral phases subject to attack by the lixiviant are the 
manganese, iron oxide, and accessory mineral phases. All 
lixiviants used in the four hydrometallurgical processes are 
selected for maximum extraction of Co, Cu, and Ni from the 
manganese and iron oxide mineral phases except for HCi 
which also extracts manganese. This implies that the 
minerals and elements in the accessory mineral phase are 
only unintentionally modified from the form in which they 
originally occur in the nodules. The elements associated with 
this accessory mineral phase are Al, K, Na, Si, and possibly 
Cr and Zr. For the smelting process, all phases of the nodule 
are affected. 



Table 1. — Composition off Clarion-Ciipperton Fracture Z one area Pacific manganese nodules 



Element 



Mean 



Median 



Element 



Mean 



Median 



Aluminum pet.. 

Antimony M-g/g-- 

Arsenic M-g^g- 

Barium pet.. 

Beryllium M-Q/g- 

Bismuth M-g^g- 

Boron M-g/g- 

Bromine M-g^g- 

Cadmium M-g/g-- 

Caleium pot.. 

Carbon pet.. 

Cerium (Jig/g- 

Cesium M-g/g- 

Chlorine pet.. 

Chromium M.g/g- 

Cobalt pet.. 

Copper pet.. 

Dysprosium M-g/g-- 

Erbium M-g/g- 

Europium ....__ |xg/g.. 

Fluorine ^g/g- 

Gadolinium tJ-g/g.. 

Gallium M-g/g- 

Germanium M-g/g- 

Gold ng/g.. 

Hafnium ixg/g.. 

Holmium M-g/g- 

Iodine M-g/g- 

Iridium ng/g- 

Iron pet.. 

Lanthanum MEl/g - 

Lead pot.. 

Lithium Mg/g- 

Lutetium M-g/g-- 

Magnesium pet.. 

Manganese pet.. 

Mercury ng/g.. 



2,9 


2.5-3.0 


37 


36 


159 


164 


0.277 


0.200-0.220 


4 


2 


21 


23 


273 


221 


500 


500 


12.3 


10-15 


1.7 


1.5-2.0 


0.19 


0.19 


532 


340 


0.75 


<0.7 


0.53 


0.78 


27 


15-20 


0.24 


0.20-0,30 


1.02 


1.00-1.10 


31 


32 


20 


23 


8 


7 


130 


<100 


32 


32 


11 


6 


42 


37 


1.93 


1.92 


6 


5 


4 


4 


510 


230 


9.1 


4,3 


6.9 


6-7 


160 


135 


0.045 


0,040-0,050 


160 


100 


1.8 


2 


1.65 


1.50-1.75 


25.4 


26-27 


152 


85 



Molybdenum pet 

Neodymium ^.g/g 

Nickel pet 

Niobium |xg/g 

Nitrogen (NO3") y-g/g 

Palladium ng/g 

Phosphorus (P2O5) (ig/g 

Platinum ng/g 

Potassium pet 

Praseodymium p.g/g 

Radium pg/g 

Rhenium ^.g/g 

Rubidium M-g/g 

Ruthenium ng/g 

Samahum j^g/g 

Scandium M-g/g 

Selenium jjig/g 

Silicon pet 

Silver ng/g 

Sodium pet 

Strontium pet 

Sulfur (S04°) pet 

Tantalum M-g/g 

Tellurium M-g/g 

Terbium (xg/g 

Thallium ixg/g 

Thorium M-g/g 

Thulium M-g/g 

Tin |xg/g 

Titanium pet 

Tungsten M,g/g 

Uranium M-g/g 

Vanadium pet 

Ytterbium M-g/g 

Yttrium M-g/g 

Zinc pet 

Zirconium pet 



0.052 


0,050-0.060 


159 


138 


1.28 


1.30-1.40 


74 


80 


560 


400 


6.2 


6.3 


2,300 


2,100 


97 


110 


1,01 


0.80-0.90 


36 


34 


8.5 


5.1 


<0.2 


INS 


15 


15 


18 


INS 


35 


32 


10 


10 


52 


53 


7.6 


6.0-6.5 


101 


39 


2.79 


2.00-2.25 


0,045 


0.040-0.050 


1,84 


0,40 


11 


11 


216 


214 


5.4 


5 


169 


160 


28 


21 


2.3 


2 


108 


80 


0.53 


0,40-0,50 


76 


80 


6,8 


5 


0,047 


0.040-0,050 


20.5 


18 


133 


111 


0.14 


0,10-0,15 


0.035 


0,030-0,040 



INS Insufficient data for median. 



In the five processes, three lixiviants are used: ammonia- 
ammonium carbonate in the two ammonia leach processes, 
sulfuric acid in the sulfuric acid process and the smelting 
process, and hydrochloric acid in the hydrochloric acid 
process. The major anion combining forms for the elements 
are carbonate (CO3 ), sulfate (SO4 ), and chloride (CI"), 
respectively. Therefore, most compounds present in the 
tailings would be a form of one of the preceding anions 
(depending on process type), an oxide or hydroxide, and/or 
remain unaltered from the original nodule feed material (for 
example, silicates). 



The predictions of physical and chemical characteristics 
made in this report are based on limited data from other 
sources (2), process flowsheets and anticipated reactions, 
solubilities, efficiencies obtained in tailings washings, and, in 
the case of Cuprion tailings, information obtained on pilot 
plant-generated material. Some estimates are subjective, 
reflecting the authors' conception of the process. The values 
reported therefore are estimates only and should not be 
construed as necessarily representing the composition of 
any tailings that will be produced in a full-scale plant. 



PROCESS DESCRIPTIONS 



Each of the five processes considered as feasible for 
first-generation manganese nodule processing is presented 
in abbreviated form. More thorough discussions of these 
processes are given elsewhere (2, 6). 

GAS REDUCTION AND 
AMMONIACAL LEACH PROCESS 

The gas reduction and ammoniacal leach process is a 
three-metal process in which Cu, Ni, and Co are liberated by 
an oxidizing ammonia-ammonium carbonate leach following 
the high-temperature reduction of manganese dioxide by 
synthesis gas. Copper and nickel are coextracted by liquid ion 
exchange reagents and are selectively stripped and reco- 
vered by electrowinning. Cobalt is separated from the 
raffinate by precipitation with hydrogen sulfide and is 
recovered from the sulfide precipitate, along with some Ni, 



Zn, and Cu, by selective leaching and hydrogen reduction. 
The metal-free raffinate is recycled to provide leach liquor 
and for washing tailings from the process. Ammonia and 
ammonium carbonate are recovered from leach tailings by 
steam stripping. A simplified block diagram of this process is 
shown in figure 2. This process is an adaptation of the Caron 
process presently used on nickel laterites at Nicaro, Cuba, 
and Greenvale, Australia (1, 8). The major differences 
between the nodule process and the Caron laterite process 
are the methods of metal separation and purification. 

CUPRION AMMONIACAL 
LEACH PROCESS 

The Cuprion process is a three-metal process in which Co, 
Cu, and Ni are liberated in an ammonia-ammonium 
carbonate leach following a reduction-leach step. Carbon 



Nodules 



Carbon dioxide - 
carbon monoxide 



Grinding and 
drying 



Waste 
containment 



Malceup- 
water 



Chemical 
reduction 



Nicltel 



Copper 



Cobalt 



Electro- 
winning 




Nicltel 
stripping 



Electro- 
winning 



Copper 
stripping 



Liquid -solid 
separation 



Metal-bearing 
solution 



Nickel-copper 
liquid ion 
exchange 



Cobalt 
recovery 



Hydrogen sulfide 



Ammonia 
recovery 



Makeup 
ammonia 



Figure 2. — Gas reduction and ammoniacal leach process. 



Nodules 



Carbon monoxide 



Grinding 



Chemical 
reduction 



Solution 
recycle 



Nickel 

_L_ 



Electro- 
winning 



teaching- 
reduced pulp 
preparation 



Waste 
containment 



Nickel r-* 
stripping 



Copper 

t 



Cobalt 



Electro- 
winning 



Copper 
stripping 



Leaching- 

liquid-solid 

separation 



Makeup 
water 



Metal-bearing 
solution 



Nickel-copper 

liquid ion 
H exchange 



Cobalt 
recovery 



Hydrogen sulfide 



Ammonia 
recovery 



f 
Makeup ammonia 



Figure 3. — Cuprion ammoniacal leach process. 



monoxide is used to regenerate the cuprous ion which 
reduces the manganese dioxide. Copper and nickel are 
coextracted by liquid ion exchange reagents and are 
selectively stripped and recovered by electrowinning. Cobalt 
is separated from the raffinate by precipitation with hydrogen 
sulfide and is recovered from the sulfide precipitate along 
with some Ni, Zn, and Cu, by selective leaching and 
hydrogen reduction. The metal-free raffinate is steam 
stripped to recover a high-strength ammonia solution for 
recycle to the tailings wash step, together with ammonia and 
ammonium carbonate recovered by steam stripping the 
leach tailings. A simplified block diagram of this process is 
shown in figure 3. This process is similar to the Caron 
process used for nickel laterites except that the reduction is 
done at ambient temperature by an aqueous-solid reaction 
instead of gas reduction, and the methods of metal 
separation and purification are different. 

HIGH-TEMPERATURE AND HIGH-PRESSURE 
SULFURIC ACID LEACH PROCESS 

The high-temperature and high-pressure sulfuric acid 
leach process is a three-metal process in which Co, Cu, and 
Ni are selectively leached from the nodules by strong sulfuric 
acid at high temperature and pressure. After separation of 
the nodule residue from the leach solution, the copper and 
nickel are coextracted by liquid ion exchange reagents and 
selectively stripped and recovered by electrowinning. Cobalt 
is separated from the raffinate by precipitation with hydrogen 
sulfide and is recovered from the sulfide precipitate, along 
with Some Cu, Ni, and Zn, by selective leaching and 
hydrogen reduction. The metal-free raffinate liquor is 
recycled to the washing process. Ammonia consumed in the 
process is recovered and recycled to the process for use in 



pH control. A simplified block diagram of this process is 
shown in figure 4. A basically similar process for treating 
nickel laterites has been used at Moa Bay, Cuba (3), except 
that the metal separation and purification procedures are 
different. 

REDUCTION AND HYDROCHLORIC 
ACID LEACH PROCESS 

The hydrochloric acid process is a four-metal process in 
which Co, Cu, Mn, and Ni are liberated from dried nodules by 
a high-temperature (500° C) gaseous hydrogen chloride 
treatment of nodules. Hydrogen chloride reduces manga- 
nese dioxide to manganous chloride (liberating chlorine gas) 
and also reacts with other metal oxides to form soluble 
chloride salts. A hydrolysis reaction and quench follow, 
where water is sprayed on the nodules and the iron is 
precipitated as ferric hydroxide. The nodules are leached 
with aqueous hydrochloric acid, forming a concentrated 
pregnant liquor of chloride salts. Copper is extracted by liquid 
ion exchange reagents from the pregnant liquor, stripped, 
and recovered by electrowinning. Cobalt is extracted from 
the copper raffinate by liquid ion exchange reagents, 
stripped, separated by precipitation with hydrogen sulfide, 
and is recovered from the sulfide precipitate, along with some 
Cu, Ni, and Zn, by selective leaching and hydrogen 
reduction. Nickel is extracted by liquid ion exchange reagents 
from the cobalt raffinate, stripped, and recovered by 
electrowinning. The nickel raffinate is evaporated crystal- 
izing manganese chloride as well as the other remaining 
chloride salts. The salts are dried using combustion gases in 
a countercurrent dryer. The dried salts are charged to a 
high-temperature fused salts electrolysis furnace, where 
molten manganese metal is tapped and cast as product and 



Grinding 



Leaching 



Nodules 



Water 
Sulfuric acid 



pH 
adjustment 



Liquid-solid 
separation 



Waste 
containment 



Copper 

1_ 



Electro- 
winning 



Copper 
liquid ion 
exchange 



Neutralization 



Ammonia 
recovery L 



Lime 



Makeup Makeup 
ammonia water 



Nickel Cobalts, 



Electro- 
winning 



Cobalt 
recovery 



t 
Hydrogen sulfide 



Figure 4.— High-temperature and liigh-pressure sulfuric acid leach process. 



Nickel hJ 
liquid on 
exchange 



Grinding 

and 

drying 



Nodules 



Hydro- 

chlorination- 

reduction 



Hydrochloric 
acid 



Water r 



Hydrochloric 

acid 

chlorine 

recovery 



Water 
storage 



Hydrolysis 



Leach 
liquid-solid 
separation 



Waste 
containment 



1 [ 



Copper 

liquid on 
exchange 



T 



Cobalt 
liquid on 
exchange 



T 



Nickel 
liquid on 
exchange 



± 



T 



Evaporation- 
crystallization 



1 



Electro- 
winning 



Copper 



-' Hydrogen sulfide 

1 t_ 



Cobalt 
recovery 



Cobalt 



Electro- 
winning 



-^ Nickel 



Fused 

salt 

electrolysis 



-^ Manganese 



Figure 5. — Reduction and hydrochloric acid leach process. 



R 


educing gas 










Chemical 
reduction 




Grinding and 
drying 


a NnHiili^t 








f 








Electric 
furnace 
smelting 




Ferro- 

manganese 

reduction 




Ferromanganese Cobalt^ 






' 


Gypsum 

1 °?* 


gen 








Copper 




NICKei 

t 




Oxidizing 
sulfiding 




Waste 
treatment 




Electro- 
winning 




Electro- 
winning 




















































pH 
adjustm'ent 






Copper 
liquid ion 
exchange 






Neutralization 






Nickel 
liquid ion 
exchange 




' 








»- 






Leaching- 
liquid-solid 
separation 












1 




















* 
























L 






Ammonia 
recovery 




Cobalt 
recovery 














Waste 






c 


ontainment 








Hydrogen sulfid 


e 



Figure 6. — Smelting and sulfuric acid leach process. 



chlorine gas is liberated. Excess hydrogen chloride gas in the 
process is recovered and recycled. Generated chlorine gas is 
recovered, dried, and delivered to a local chemical complex 
which, in exchange, returns makeup hydrogen chloride to the 
process. This process has no direct analog in existing ore 
processing. A simplified block diagram of this process is 
shown in figure 5. 

SMELTING AND SULFURIC 
ACID LEACH PROCESS 

The nodule smelting process is a combination pyrometal- 
lurgical and hydrometallurgical treatment of nodules to 
recover the value metals, Co, Cu, and Ni, with the option of 
recovering ferromanganese. The smelting process produces 
a slag from which ferromanganese is recovered and a matte 
composed primarily of Co, Cu, Ni, and S. The ma tte is 
"granulated, slurried, and selectively leached with sulfuric acid, 
at elevated temperature and pressure (9). The leach residue 



and metalliferous solution are separated by a series of 
filtering and washing stages. After liquid-solid separation, 
copper and nickel are selectively extracted by liquid ion 
exchange, stripped from the ion e xchan ge Nquid into a 
depleted electrolyte, and recovered by electrowinning. 
Cobalt is separated from the raffinate by precipitation with 
hydrogen sulfide and is recovered from the sulfide precipi- 
tate, along with some Cu, Ni, and Zn, by selective leaching 
and hydrogen reduction. Ammonia consumed in the process 
is recovered by lime boil and is recycled to the process for 
use in pH control. A simplified block diagram of this process 
is shown in figure 6. The reject waste material in this process 
consists of slags that are produced during smelting and 
refining and a small amount (~1 pet) of tails from sulfide 
matte leaching. Many industrial analogs are available for 
nonferrous smelting processes. The physical characteristics 
of nodule reject slags are expected to be similar to those of 
glassy, inert slags from present smelting operations, 
whereas the chemical characteristics may differ. 



PHYSICAL CHAHACTERISTICS 



The predicted physical characteristics for the five selected 
processes are presented in four groups. Because of 
similarities between the gas reduction and Cuprion ammo- 
niacal leach processes, they are discussed together; the 



other three are discussed separately. Presented in the 
ammoniacal leach processes section is an analysis of a pilot 
plant-generated Cuprion waste. Table 2 is a summary of the 
predicted physical properties of the reject waste materials. 



Tible 2. — Predicted physical cliaracteristics of 
manganese nodule reject waste material 





Settling density, 


Grain size, 




Process type 


pet solids 


mesh 


Stability 


Gas reduction and 


50-60 


-200 


Good. 


Cupnon ammonical 








leach process. 








High-temperature and 


40-50 


-200 


Good. 


high-pressure sulfuric 








acid leach process. 








Reduction and 


30-50 


-270 


Fair. 


hydrochloric acid leach 








process. 








Smelting and sulfuric acid 


NAp 


>10 


Excellent. 


leach process.' 









NAp Not applicable (dry inert slags). 
' Does not include leach residues from sulfide leaches which comprise only 
about 1 pet of the waste material. 



Table 3. — Physical composition of Cuprion pilot 
plant-generated reject waste material* 

Parameter Results 

Grain size distribution 100 pet pass 74 [im. 

50 pet pass 6 (jLm. 

Specific gravity 3.19 (dry solids). 

Triaxial shear 38° friction angle. 

5 psi cohesion. 

Permeability 8.46 x 10"* cm/see at 95 pet 

^ maximum density. 

Maximum density pcf.. 90.1 

Atterberg limits: 

Liquid pet.. 45 

Plastic pet.. 41.2 

Soil class.. ML (lean silt). 

Slurry density wt-pet,. 41.8 

' Analysis provided by R. W. McKibbln, mining engineer, Spokane (Wash.) 
Research Center. 



GAS REDUCTION AND CUPRION 
AMMONIACAL LEACH PROCESSES 

The physical characteristics of nodule reject waste 
material from the gas reduction and Cuprion ammoniacal 
leach processes are expected to be similar to those of nickel 
laterite tailings generated by the Caron process. These 
wastes from laterite processing settle to relatively high 
densities and become a mechanically stable waste. The 
major difference between the laterite tailings and manganese 
nodule tailings would be the relative iron and manganese 
contents. Laterite tailings are higher in iron and lower in 
manganese, while nodule tailings will be of an opposite 
composition. This iron-to-manganese ratio should have little 
effect on the physical parameters of the respective tailings. 
Typical physical characteristics of these tailings would be a 
particle size of'minus 200 mesh, settling densities of 50 to 60 
pet (percent solids), and good long-term stability (1, 8). 
'Table 3 gives the analysis of a pilot plant-generatedTrepect 
waste material as reported by the Bureau's Spokane (Wash.) 
Research Center. These results may not be typical of final 
rejects produced during full-scale plant operation because of 
variances that occur during pilot plant operation. 

HIGH-TEMPERATURE AND HIGH-PRESSURE 
SULFURIC ACID LEACH PROCESS 

The physical characteristics of nodule reject waste 
material from the high-temperature and high-pressure 
sulfuric acid leach process should be similar to the nickel 
laterite tailings generated at Moa Bay, Cuba. These wastes 
settle to relatively high densities and become mechanically^ 
stable. As noted in the previous section, the major difference 
between the laterite tailings and the nodule reject waste 



material is the iron and manganese content. This 
iron-to-manganese ratio should have little effect on the 
physical properties. Expected physical characteristics of the 
tailings are a particle size of minus 200 mesh, settling 
densities of 40 to 50 pet solids, and good long-term stability. 

REDUCTION AND HYDROCHLORIC 
PROCESS ACID LEACH 

The physical characteristics of nodule reject waste 
material from the reduction and hydrochloric acid leach 
process has no known existing mineral processing analog. 
Based on very limited information, a particle size of less than 
270 mesh and settling densities of 30 to 50 pet with fair 
long-term stability are anticipated. This material should be a 
hydroxide sludge with acid insoluble silicates such as clays 
and feldspars. Because of the chloride concentration of the 
waste, the possibility of rainwater leaching is increased. 

SMELTING AND SULFURIC 
ACID LEACH PROCESS 

The physical characteristics of the nodule reject waste 
material (slags and tailings) from the smelting and sulfuric 
acid leach process should be similar to wastes generated by 
nonferrous smelters. These wastes are generally large, inert, 
glassy materials that contain the elements sealed in an 
impermeable glass matrix. These slags are used for fill 
material and road beds among other uses. The physical 
parameters of nodule smelting slags should be similar to the 
preceding description with particle sizes generally greater 
than 10 mesh, excellent settling densities, and excellent 
long-term stability. 



CHEMICAL CHARACTERISTICS 



The predicted chemical characteristics are divided into four 
groups. The gas reduction and Cuprion ammoniacal leach 
processes are combined in one group as the compositions of 
these reject waste materials are expected to be similar. The 
remaining three processes are described separately. Also 
presented with the gas reduction and Cuprion sections are 
results of analyses of pilot plant-generated Cuprion reject 
waste material. The results of the EP toxicity test on this 
same material are also presented. 

GAS REDUCTION AND CUPRION 
AMMONIACAL LEACH PROCESSES 

Chemical characteristics of these nodule reject waste 
materials should be similar to those of nickel laterite tailings 



from the Caron process but with a higher manganese and 
lower iron content. Table 4 lists the 1 6 elements of interest, 
their estimated concentration ranges, and the probable 
compound forms expected to be present. The principal 
constituent of the waste will be manganese as manganese 
carbonate, hydroxide, and/or oxide. The other major 
constituent would be iron hydroxide. These two elements and 
their compounds should account for over 80 pet of the tailings 
composition. The principal anion forms for this waste material 
would be carbonate (CDs') and hydroxide (OH) with some 
oxides present. Also present will be unreacted accessory 
minerals such as clays, f eldspars, and silica. 

Table 5 lists the results of the chemical analysis of a 
Cuprion pilot plant-generated reject waste material, and 
compares well with the predicted compositions listed in table 



Table 4. — Predicted chemical composition of manganese nodule reject waste material 

from leach processes 



Remaining in tailings, Estimated concentration Probable constituents 
Element pet range, wt-pct present 


Remaining in tailings, Estimated concentration Probable constituents 
pet range, wt-pct present 


Gas reduction and Cuprion ammoniacal leach 


High-temperature and high-pressure sulfuric acid leach 


Antimony -90 0.002-0.008 Iron or manganese 

antimonide. 
Arsenic -90 .003- .010 Iron or manganese 

arsenate. 

Barium -10 .150- .300 BaS04 

Beryllium -90 .0005- .0010 BeCOa, BeO 

Cadmium -90 .0001- .0020 CdCOj, Cd(0H)2 

Chromium -90 .0010- .0020 Cr203, Cr(0H)3 

Cobalt -30 .050- .1 50 Co{OH)2, C0CO3 

Copper -10 .050- .150 Cu(0H)2, CUCO3 

Iron -100 5.0 -10.0 Fe(0H)3, FeC03, 

Fe(0H)2, FeO-OH 

Lead -90 .020 - .050 PbC03, Pb(0H)2 

Manganese -100 25 -35 MnC03, Mn(0H)2, 

MnO, Mn02 
Molybdenum -30 .01 - .02 M02O3, 

(NH4)2Mo04? 

Nickel -10 .15 - .30 Ni(0H)2, NiC03 

Selenium -90 .0025- .0050 Iron or manganese 

cplonoto 

Thallium -70 .01 - .02 TI(0H)3 

Zinc -60 .075- .125 Zn(0H)2 


-50 0.001 - 0.003 Iron or manganese 

antimonide. 
-90 .003- .010 Iron or manganese 

arsenate. 
-100 .150 - .300 BaS04 
-90 .0001- .0002 BeS04-4H20, BeO 
<1 <.0005 CdS04 
-90 <.0010- 0020 Cr203, Cr2(S04)3 
-33 .050 - .150 CoO 
-5 .002 - .008 CuO, Cu(0H)2 
-100 6 -10 FezOs, Fe(0H)3 

KFe3(S04)2(OH)6 
-100 .03 - .06 PbS04 
-95 25 -35 MnOa, MnO 

-100 .04 - .06 MOaOg 

-5 .10 - .20 NiO 
-90 .0025- 0050 Iron or manganese 

selenate. 
-80 .01 - .02 Tl2(S04)3 
-10 .01 - .03 Zn(0H)2, ZnO 


Reduction and hydrochloric acid leach 


Smelting and sulfuric acid leach 


Antimony -10 0.0005-0.0020 Iron antimonides. 

Arsenic -10 .0005- .0020 Iron arsenates. 

Barium -10 .015- .030 BaS04 

Beryllium -1 <.0001 BeO 

Cadmium ~1 <.0005 CdCl2 

Chromium -90 .001 - .002 Cr203, CrCl3 

Cobalt -1 .002 - .004 C0CI2 

Copper -1 .01 - .02 Cu(0H)2, CUCI2 

Iron -100 6 -10 Fe(0H)3 

Lead -10 .003- .006 PbCl2, PbO 

Manganese -5 1 - 2 Mn02, MnCl2 

Molybdenum —1 .0005- .0010 M02O3 

Nickel -1 .01 - .02 NiClz 

Selenium -10 .0005- .0020 Iron selenates. 

Thallium -50 .005- .015 TI(0H)3 

Zinc -1 .001 - .002 ZnCl2 


-20 0.001 - 0.002 Iron antimonides. 
-10 .002- .004 Iron arsenates. 
-100 .30 - .50 BaO 
-10 <.0001- .0001 BeO 
-50 .001 - .002 Cd, CdO, CdS 
-50 .001 ■ .003 Cr, CrzOa 
-10 .04 - .06 Co, CoO, CoS 
-10 .10 - .30 Cu, CuO, CuS 
-30 3-5 Fe, FeO 

-1 .001 - .005 Pb, PbO, PbS 

-5 2-4 Mn, MnO 
-10 .002 - .005 M02O3 

-5 .10 - .15 Ni, NiO, NiS 
-10 .0005- .0020 Iron selenates. 
-50 .01 - .02 TI2O3 

-1 .005 - .01 Zn, ZnO, ZnS 



Table 5. — Chemical composition off Cuprion pilot 
plant-generated reject waste material, 
weight-percent 



Element 

Antimony 

Arsenic 

Barium 

Beryllium 

Cadmium 

Chromium 

Cobalt 

Copper 

Iron 

Lead 

Manganese 

Molybdenum 

Nickel 

Selenium 

Thallium 

Zinc 



Concentration 
wt-pct 

0.004 

.005 

.004 

.0005 

.003 

.005 

.18 

.14 
6 

.050 
32 

.02 

.25 

.0001 

.016 

.11 



Table 6. — EP toxicity results on Cuprion pilot 

plant-generated reject waste material, 
concentration, micrograms per milliliter 

Element 



Arsenic 

Barium , . . 
Cadmium . 
Chromium 

Lead 

Mercury . . 
Selenium . 
Silver 



Maximum allowed 


Amount leached 


5.0 


0.004 


100.0 


4.4 


1.0 


.06 


5.0 


.14 


5.0 


.6 


.2 


.019 


1.0 


.002 


5.0 


<.3 



4. X-ray diffraction showed MnCOa as the principal 
compound. 

Table 6 gives the results of the EP toxicity test on this same 
material. All of the elements are well within the limits as 
outlined by EPA (4-5). 

HIGH-TEMPERATURE AND HIGH-PRESSURE 
SULFURIC ACID LEACH PROCESS 

Chemical characteristics of this nodule reject waste 
material should be similar to those of tailings from laterite 
processing at Moa Bay, Cuba, but have a higher manganese 
and lower iron content. Table 4 lists the 16 elements of 
interest, their estimated concentration ranges, and the 
probable compound forms that may be present. 

The major constituent in this waste should be manganese 
as manganese dioxide or oxide together with iron hydroxide. 
These two elements and their compounds account for over 
80 pet of the tailings composition. The principal anion forms 
are hydroxide, oxide, and sulfate. Also present will be the 
unreacted accessory mineral phase constituents such as 
clays, feldspars, and silica. 

REDUCTION AND HYDROCHLORIC 
ACID LEACH PROCESS 

The chemical characteristics of nodule reject waste 
material from this process will be different from any of the 
other processes. Table 4 lists the 16 elements of interest, 
their estimated concentration range, and the probable 
compounds that could be present. The largest constituent of 
this waste material should be the acid insoluble fraction of the 
nodules; clays, feldspars, and silica. The remainder should 



10 



be iron hydroxide, other hydroxides, and entrained chloride 
salts not removed during the washing and filtration steps. 
The principal anion forms for the reject waste material should 
be silicate, hydroxide, and chloride. 

SMELTING AND SULFURIC 
ACID LEACH PROCESS 

The chemical characteristics of this nodule reject waste 
material (slags and tailings) will be similar to slags and 



tailings produced by nonferrous smelting processes. Table 4 
lists the 16 elements of interest, their estimated concentra- 
tions, and the probable compound forms that may be present. 
The major constituents of this material would be silicate 
glass and iron. The leach residues (about 1 pet of the total 
material) should contain trace levels of metal sulfides not 
leached during processing. Most elements present in the 
slag will exist in the metallic state or as oxides. Only a small 
amount of sulfides will be present from the leached residue. 



SUMMARY AND CONCLUSIONS 



As part of the Bureau work on analysis and characteriza- 
tion of manganese nodule processing rejects, the physical 
and chemical composition of the reject waste materials from 
potential manganese nodule processing are estimated. 
These reject waste materials are based on five process 
flowsheets: the gas reduction and ammoniacal leach 
process, the Cuprion ammoniacal leach process, the 
high-temperature and high-pressure sulfuric acid leach 
process, the reduction and hydrochloric acid leach process, 
and the smelting and sulfuric acid leach process. In these five 
processes only three lixiviants are used; ammonium- 
ammonium carbonate, sulfuric acid, and hydrochloric acid. 
Other lixiviants, such as nitric acid, are being considered, but 
the three discussed for the five processes are the most 
feasible for first-generation manganese processing^ 

The physical characteristics of the tailings were predicted 
based on limited available information on laterite processing. 

Based on limited information, wastes from the gas 
reduction and Cuprion ammoniacal leach processes should 
have moderately high settling densities (50 to 60 pet), be 
minus 200 mesh, and have good long-term stability. The 
high-temperature and high-pressure sulfuric acid process 
wastes should be similar to wastes from the ammoniacal 
processes. The reduction and hydrochloric acid process 
would have somewhat lower settling density (30 to 50 pet), 
be about minus 270 mesh, and have only fair long-term 
stability. Wastes from the smelting and sulfuric acid process 



would be primarily glassy, inert slags at >10 mesh with 
excellent long-term stability. 

The chemical characteristics were predicted based on the 
major lixiviant used and the process conditions. Estimates of 
the concentration of 1 6 elements in the reject waste material 
and the compounds present are presented, as well as 
estimates of the percentage of original feed remaining after 
processing. 

Results of the EPA EP toxicity test on a pilot plant- 
generated reject waste material from the Cuprion process 
were well below maximum limits for designation as 
hazardous by EP toxicity. 

All estimates and predictions are made based on no 
manganese recovery in the two ammoniacal processes and 
the high-temperature and high-pressure sulfuric acid pro- 
cess. If recovery and purification of manganese from these 
reject waste materials prove viable, then the physical and 
chemical characteristics of the wastes would be altered. 

It appears that the reject waste material generated by the 
five outlined processes may have only minor environmental 
implications. Leachates from EP toxicity of the two ammo- 
niacal leach wastes, the sulfuric acid leach waste, and the 
smelting leach waste should be well below maximum limits 
for classification as hazardous waste. Reject waste material 
from the hydrochloric acid leach process may have 
difficulties staying below EP toxicity limits because of soluble 
chloride salts. 



REFERENCES 



1. Alonso, A., and J. Daubenspek. Modifications in Nicaro 
Metallurgy. Trans. Met. Soc. of AIME, v. 217, 1960, pp. 253-257. ' 

2. Dames and Moore, and E.I.C. Corporation. Description of 
Manganese Nodule Processing Activities for Environmental Studies, 
Vol. III. Processing Systems Technical Analysis, U.S. Dept. of 
Commerce-NOAA, Office of Marine Minerals, Rockville, Md., 1977, 
540 pp.; NTIS PB 274912 (set). 

3. Duvesteyn, W. P. C, G. R. Wicker, and R. E. Doane. An 
Omnivorous Process for Laterite Deposits. Proc. Internal. Laterite 
Symp., ed. by D. J. I. Evans, R. S. Shoemaker, and H. Veltman. 
Society of Mining Engineers of AIME, New York, 1979, pp. 553-570. 

4. Federal Register. Part IV, Environmental Protection Agency: 
Hazardous Waste; Proposed Guidelines and Regulations and 
Proposal on the Identification and Listing. V. 43, No. 243, Dec. 18, 
1978, pp. 58946-59028; 110-CFR, Part 250. 

5. Federal Register. Parts ll-IX, Environmental Protection Agency: 
Hazardous Waste and Consolidated Permit Regulations. V. 1 15, No. 



98, May 19, 1980, Book 2, pp. 33063-33285; 110-CFR, Parts 
260-265. 

6. Haynes, B. W., and S. L. Law. Updated Process Flowsheets for 
Manganese Nodule Processing. BuMines unpublished manuscript; 
available for consultation at Bureau of Mines Avondale Research 
Center, Avondale, Md. 

7. Haynes, B. W., S. L. Law, and D. C. Barron. Mineralogical and 
Elemental Description of Pacific Manganese Nodules. BuMines 10 
8906, in press. 

8. Reid, J. G. Operations at the Greenvale Nickel Project Mine and 
Refinery. Proc. Internal. Laterite Symp., ed. by D. J. I. Evans, R. S. 
Shoemaker, and H. Veltman. Society of Mining Engineers of AIME, 
New York, 1979, pp. 368-381. 

9. Sridhar, R., W. E. Jones, and J. S. Warner. Extraction of 
Copper, Nickel, and Cobalt From Sea Nodules. J. Metals, v. 28, 
1976, pp. 32-37. 



it U.S. GOVERNMENT PRINTING OFFICE: 1982—383-688/8681 



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